Trophic interactions and direct physical effects control phytoplankton biomass and production in an estuary
A.E. Alpine, J. E. Cloern
1992, Limnology and Oceanography (37) 946-955
San Francisco Bay has recently been invaded by the suspension-feeding clam Potamocorbula amurensis. Previous work has shown that phytoplankton biomass in the upper estuary is low (2-3 mg Chl a m-3) during seasonal periods of high river flow and short residence time and it is usually high (peak >30 mg...
Effects of uranium mining discharges on water quality in the Puerco River basin, Arizona and New Mexico
P. C. Van Metre, J. R. Gray
1992, Hydrological Sciences Journal (37) 463-480
From 1967 until 1986, uranium mine dewatering increased dissolved gross alpha, gross beta, uranium and radium activities and dissolved selenium and molybdenum concentrations in the Puerco River as indicated by time trends, areal patterns involving distance from the mines and stream discharge. Additionally, increased dissolved uranium concentrations were identified in...
The supply and demand for pollution control: Evidence from wastewater treatment
V.D. McConnell, G. E. Schwarz
1992, Journal of Environmental Economics and Management (23) 54-77
This paper analyzes the determination of pollution control from wastewater treatment plants as an economic decision facing local or regional regulators. Pollution control is measured by plant design effluent concentration levels and is fully endogenous in a supply- and-demand model of treatment choice. On the supply side, plant costs are...
Late-glacial to holocene changes in winds, upwelling, and seasonal production of the northern California current system
C. Sancetta, M. Lyle, L. Heusser, R. Zahn, J.P. Bradbury
1992, Quaternary Research (38) 359-370
A core 120 km off the coast of southern Oregon was examined for changes in lithology, diatoms, and pollen over the past 30,000 yr. Primary production during the late Pleistocene was about half that of the Holocene. Evidence from diatoms and pollen indicates that summer upwelling was much weaker, implying...
The aqueous photolysis of α-pinene in solution with humic acid
Marvin C. Goldberg, Kirkwood M. Cunningham, George R. Aiken, Eugene R. Weiner
1992, Journal of Contaminant Hydrology (9) 79-89
Terpenes are produced abundantly by environmental processes but are found in very low concentrations in natural waters. Aqueous photolysis of solutions containing α-pinene, a representative terpene, in the presence of humic acid resulted in degradation of the pinene. Comparison of this reaction to photolysis of α-pinene in the presence of...
The stable isotope geochemistry of acid sulfate alteration
R. O. Rye, P. M. Bethke, M.D. Wasserman
1992, Economic Geology (87) 225-262
Acid sulfate wall-rock alteration, characterized by the assemblage alunite + kaolinite + quartz + or - pyrite, results from base leaching by fluids concentrated in H 2 SO 4 . Requisite amounts of H 2 SO 4 can be generated by different mechanisms in three principal geologic environments: (1) by atmospheric oxidation of sulfides in the supergene environment,...
Effects of nutrient management on nitrate levels in ground water near Ephrata Pennsylvania
David W. Hall
1992, Groundwater (30) 720-730
Effects of the implementation of nutrient management practices on ground-water quality were studied at a 55-acre farm in Lancaster County, Pennsylvania, from 1985-90. After nutrient management practices were implemented at the site in October 1986, statistically significant decreases (Wilcoxon Mann-Whitney test) in median nitrate concentrations in ground- water samples occurred...
Effects of climatic change and climatic variability on the Thornthwaite moisture index in the Delaware River basin
G. J. McCabe Jr., D.M. Wolock
1992, Climatic Change (20) 143-153
The Thornthwaite moisture index is useful as an indicator of the supply of water in an area relative to the demand under prevailing climatic conditions. This study examines the effects of long-term changes in climate (temperature and precipitation) on the Thornthwaite moisture index in the Delaware River basin. Temperature and...
An improved method for field extraction and laboratory analysis of large, intact soil cores
J.A. Tindall, K. Hemmen, J.F. Dowd
1992, Journal of Environmental Quality (21) 259-263
Various methods have been proposed for the extraction of large, undisturbed soil cores and for subsequent analysis of fluid movement within the cores. The major problems associated with these methods are expense, cumbersome field extraction, and inadequate simulation of unsaturated flow conditions. A field and laboratory procedure is presented that...
Arrival times and temporal moments of breakthrough curves for an imperfectly stratified aquifer
R.L. Naff
1992, Water Resources Research (28) 53-68
Using concepts developed in an earlier study, a solution in Laplace transform space is obtained for transport of resident concentration in an imperfectly but yet highly stratified porous medium. The flow field, into which an instantaneous pulse of tracer is injected, is taken to be steady and mean uniform parallel...
Late Cretaceous inoceramid bivalves of the Kuskokwim Basin, southwestern Alaska, and their implications for basin evolution
W.P. Elder, S. E. Box
1992, Journal of Paleontology (66)
Upper Cretaceous rocks of the Kuskokwim Group are exposed in a large region of southwestern Alaska and are mainly composed of deformed turbidite deposits that contain few fossils other than inoceramid bivalves. This paper documents the taxonomy of the inoceramids in the Kuskokwim Group, develops an inoceramid...
Use of weather types to disaggregate general circulation model predictions
L.E. Hay, G. J. McCabe Jr., D.M. Wolock, M. A. Ayers
1992, Journal of Geophysical Research (97) 2781-2790
General circulation models (GCMs) simulate climatic conditions with a grid cell resolution on the order of 100,000 km2. This resolution is inadequate to assess the effects of climatic change on water resources at a regional scale. A method has been developed that uses weather-type analysis as...
Pesticide residues in ground water of the San Joaquin Valley, California
Joseph L. Domagalski, N. M. Dubrovsky
1992, Journal of Hydrology (130) 299-338
A regional assessment of non-point-source contamination of pesticide residues in ground water was made of the San Joaquin Valley, an intensively farmed and irrigated structural trough in central California. About 10% of the total pesticide use in the USA is in the San Joaquin Valley. Pesticides detected include atrazine,...
Upper Cretaceous Shannon Sandstone reservoirs, Powder River Basin, Wyoming: Evidence for organic acid diagenesis?
Paula L. Hansley, Vito F. Nuccio
1992, American Association of Petroleum Geologists Bulletin (76) 781-791
Comparison of the petrology of shallow and deep oil reservoirs in the Upper Cretaceous Shannon Sandstone Beds of the Steele Member of the Cody Shale strongly suggests that organic acids have had a more significant impact on the diagenetic alteration of aluminosilicate grains and carbonate cements in the deep reservoirs...
Relationship between inferred redox potential of the depositional environment and geochemistry of the Upper Pennsylvanian (Missourian) Stark Shale Member of the Dennis Limestone, Wabaunsee County, Kansas, U.S.A.
J. R. Hatch, J.S. Leventhal
1992, Chemical Geology (99) 65-82
Analyses of 21 samples collected from a core of the 52.8-cm-thick Stark Shale Member of the Dennis Limestone in Wabaunsee County, Kansas, demonstrate four cycles with two-orders-of-magnitude variations in contents of Cd, Mo, P, V and Zn, and order-of-magnitude variations in contents of organic carbon, Cr, Ni, Se and U....
Subglacial water flow inferred from stream measurements at South Cascade Glacier, Washington, USA
A. G. Fountain
1992, Journal of Glaciology (38) 51-64
The subglacial drainage system of South Cascade Glacier is inferred by examining how discharges of water, solutes and artificial tracers in streams draining the glacier respond to meltwater and precipitation on the glacier surface. Results indicate that the glacier is divided into three (two large and one...
Energy budgets and resistances to energy transport in sparsely vegetated rangeland
William D. Nichols
1992, Agricultural and Forest Meteorology (60) 221-247
Partitioning available energy between plants and bare soil in sparsely vegetated rangelands will allow hydrologists and others to gain a greater understanding of water use by native vegetation, especially phreatophytes. Standard methods of conducting energy budget studies result in measurements of latent and sensible heat fluxes above the plant canopy...
Leaks in pipe networks
Ranko S. Pudar, James A. Liggett
1992, Journal of Hydraulic Engineering (118) 1031-1046
Leak detection in water‐distribution systems can be accomplished by solving an inverse problem using measurements of pressure and/or flow. The problem is formulated with equivalent orifice areas of possible leaks as the unknowns. Minimization of the difference between measured and calculated heads produces a solution for the areas. The quality...
Patterns and rates of ground-water flow on Long Island, New York
Herbert T. Buxton, Edward Modica
1992, Groundwater (30) 857-866
Increased ground-water contamination from human activities on Long Island has prompted studies to define the pattern and rate of ground-water movement. A two-dimensional, fine-mesh, finite-element model consisting of 11,969 nodes and 22,880 elements was constructed to represent ground-water flow along a north-south section through central Long Island. The model represents...
Effects of urban storm-runoff control on ground-water recharge in Nassau County, New York
Henry Ku, Nathan Hagelin, Herbert Buxton
1992, Groundwater (30) 507-514
Before urban development, most ground-water recharge on Long Island, New York, occurred during the dormant season, when evapotranspiration is low. The use of recharge basins for collection and disposal of urban storm runoff in Nassau County has enabled ground-water recharge to occur also during the...
The effect of membrane filtration artifacts on dissolved trace element concentrations
A. J. Horowitz, K. A. Elrick, M.R. Colberg
1992, Water Research (26) 753-763
Among environment scientists, the current and almost universally accepted definition of dissolved constituents is an operational one only those materials which pass through a 0.45-??m membrane filter are considered to be dissolved. Detailed laboratory and field studies on Fe and Al indicate that a number of factors associated with filtration,...
Origin of stratiform sediment-hosted manganese carbonate ore deposits: Examples from Molango, Mexico, and TaoJiang, China
P.M. Okita, Wayne C. Shanks III
1992, Chemical Geology (99) 139-163
Carbonate and sulfide minerals from the Molango, Mexico, and TaoJiang, China, Mn deposits display similar and distinctive ??34S and ??13C patterns in intervals of manganese carbonate mineralization. ??13C-values for Mn-bearing carbonate range from -17.8 to +0.5??? (PDB), with the most negative values occurring in high-grade ore zones that are composed...
Isolation of hydrophilic organic acids from water using nonionic macroporous resins
G. R. Aiken, Diane M. McKnight, K. A. Thorn, E.M. Thurman
1992, Organic Geochemistry (18) 567-573
A method has been developed for the isolation of hydrophilic organic acids from aquatic environments using Amberlite∗ XAD-4 resin. The method uses a two column array of XAD-8 and XAD-4 resins in series. The hydrophobic organic acids, composed primarily of...
A 3D, finite element model for baroclinic circulation on the Vancouver Island continental shelf
R. A. Walters, M.G.G. Foreman
1992, Journal of Marine Systems (3) 507-518
This paper describes the development and application of a 3-dimensional model of the barotropic and baroclinic circulation on the continental shelf west of Vancouver Island, Canada. A previous study with a 2D barotropic model and field data revealed that several tidal constituents have a significant baroclinic component (the K1 in...
Radiocarbon dating of groundwater in a confined aquifer in southeast Arizona
F. N. Robertson
1992, Radiocarbon (34) 664-676
Radiocarbon, δ13C and major-element data were used to construct a geochemical framework for interpretation of the hydrological flow system in the lower San Pedro basin, southeastern Arizona, USA. The 14C and major-element data show a regional confined aquifer that extends throughout most of the basin. Groundwater ages, after correcting...
